The specific aim of this project is to characterize the structural and physical-chemical processes that participate in the metabolic balance of arterial walls by applying the principals of bioengineering and mass transport. The transmural transport of ferritin and of radiolabeled (125I) albumin, HDL, and LDL across the intact and deendothelialized intimal surfaces of adult minipig arteries and veins will be studied in a specially designed in vitro system. This system permits discrete experimental control of pertinent variables such as local chemical milieu, pressure, wall stretch, etc, at 12 contiguous sites along the length of the vessel. The uptake (M nmol cm to the minus 2) and the transmural concentration distribution (c(x) nmol cm to the minus 3 of the labeled proteins and the corresponding pattern of ferritin deposition will be measured as a function of duration (T) of exposurte, transmural pressure (p), wall strain (S), endothelial damage, and a number of vaso-active substances, e.g., noradrenalin. The c(x) will be calculated from microdensitometric measurements of silver distribution across microautoradiographic preparations. The c(x) data will be correlated with structural detail from adjacent light and electron micrographs (SEM and TEM). The four main classes of blood vessels, vein (jugular), elastic artery (thoracic aorta), muscular artery (ilio-femoral), and transitional artery (carotid), will be studied in the above manner from each of the following types of animals: normal young adult (approximately 24 mo), normal old ( approximately 12 yr), chronic balloon-injured, and hypercholesterolemic minipigs. The c(x) data from the four vessels in these four types of animals will be fitted to tentative mathematical models (equations of mass balance) to obtain numrical estimates of the parameters describing the underlying physical and chemical processes, i.e., diffusion, convection, and chemical reactions. The spatial distributions of these parameters also will be correlated with the corresponding structural composition of the vessel wall. The long-range objective of this research is to develop realistic physical-chemical models of the processes operative in the above situations as an essential point of departure in the design of future research onlocal metabolic and cellular processes in normal and arteriosclerotic vessel walls as well as in surgical prosthetic materials.